By Anonymous on Monday, January 10, 2000 - 03:37 pm:
I am having major difficulties developing a method for analysis of vitamin K in the presence of a relatively large amount of vitamin E. Can someone please post some suggestions or even some insights on the chemical nature of these two compounds. You have the potential to make me a BIG hero if I can come up with a breakthrough. Thanks in advance for your suggestions. My e-mail address is jvglass@worldnet.att.net
By Leray C on Tuesday, January 11, 2000 - 05:11 am:
The solution depends on the detection level you
need but there is a lot of HPLC methods designed
to separate liposoluble vitamins. I give you 2
ref.:
Barnett SA et al, Anal Chem 1980,52, 610-4
Jakob E et al, Internat J Vit Nutr Res 1995, 65,
31-5
Let me know your choice
You can visit my website:
http://go.to/cyberl
By Anonymous on Tuesday, January 11, 2000 - 12:51 pm:
The link above doesn't appear to work.
By Anonymous on Tuesday, January 11, 2000 - 03:39 pm:
Column: BetaBasic 18, 5 um, 150x4.6mm (Keystone Scientific, Inc.)
Mobile Phase: 75/25 Acetonitrile/methanol
Flow: 1.0 mL/min
Detection: UV @ 280 nm
By Maciej on Tuesday, January 11, 2000 - 10:35 pm:
What does mean "relatively large amount" of vit. E? Is its peak so huge thay you cannot integrate both (E & K) at the same time? If so, I may suggest you to make two separate runs (assays) for both vitamins.
In addtition, vitamin E has a large hydrophobic chain and vitamin K appears in three different sub-species, of which K1 and K2 are highly hydrophobic and the remaining K3 is not. Moreover, the latter one may appear ionized if its bisulfite derivative.
Can I know more details? Detection, column, mobile phase, others?
Greetings,
Maciej Turowski
KIT
By p van haard on Thursday, January 20, 2000 - 03:20 am:
Look at one of my papers:
van Haard PMM et al..
clin chim acta 157 (1986) pg. 221-230
applying post-column electrochemical reduction and spectrofluorometric detection.
It works also on methanolic dilutions of phytomenadione in oil
The Dutch central pharmacists reference lab (LNA) experienced recently the same problems as you did only in pharmapreparations of vit k1 (UV-detection) containing surplus vitamin E as a anti-oxidant.
By Anonymous on Sunday, May 9, 2004 - 02:31 am:
Having difficulty with the deratization of B6 vitamers from plasma. any simple procedures available
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